Giardia lamblia lives in two distinctly different habitats in its life depending on what part of the life cycle it is in. First would be the trophozoite (vegetative) form found in the fecal contaminated soils, streams, ponds and other sources of water worldwide (Mayo Clinic 2014). Highly populated areas of giardiasis infections have been found in areas of low hygienic water conditions such as, the developing counties of Africa, and the middle east. Highly developed countries such as the United States also contain populations of giardiasis. Most commonly found in the northern states, the highest concentration of giardiasis is found in the state of Vermont (containing a number of 29.7 on the map below).The reasoning behind this is unknown, although giardiasis is most commonly present in areas that are densely populated, and contain a high level of travelers returning from developing countries. Traveling being one of the main reasons for giardiasis infections being reported most often during summer months (CDC 2014).

Figure 1. Map of United States from 2010 showing the presence of giardiasis infection per 100,000 people.

Other organisms living in the same environments can vary greatly depending on which part of the life cycle Giardia lamblia is in. When it is in its cystic lifecycle outside of the body, Giardia lamblia lives alongside other many other parasites, micro-organisms, and bacteria found in fecal matter.  Since Giardia lamblia primarily inhabits lives in streams and bodies of water, there are many aquatic animals living alongside the organism such as otters, beavers, and fish (CDC 2014). Once inside a mammal, Giardia lamblia, attaches using its two ventral adhesion disks found on top the the organisms body, to the small intestine of the host. The parasite resides there until it leaves the body in its cystic form through the hosts fecal matter (Jelinek, T. and S. Neifer. 2013).

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